using System;

 using System.Collections.Generic;

 using System.Linq;

 namespace Linq101

 {

     class CustomSequence

     {

         public void Linq98()

         {

             int[] vectorA = { , , , ,  };

             int[] vectorB = { , , , ,  };

             int result = vectorA.Combine(vectorB, (a, b) => a * b).Sum();

             Console.WriteLine(result);

         }

     }

     public static class CustomSequenceOperators

     {

         public static IEnumerable<int> Combine(this IEnumerable<int> first, IEnumerable<int> second, Func<int, int, int> func)

         {

             //List<int> list=new List<int>();

             using (IEnumerator<int> e1 = first.GetEnumerator(), e2 = second.GetEnumerator())

             {

                 while (e1.MoveNext() && e2.MoveNext())

                 {

                     yield return func(e1.Current, e2.Current);

                     //list.Add(func(e1.Current, e2.Current));

                 }

             }

             //return list;

         }

     }

 }